Radio antenna tower



Dz uuulu l IVV June 1-1, 1946. E. w. RIEMENSCHNEIDER ETAL 2,401,799

I RADIO ANTENNA TOWER Filed Aug. 4, 1941 3 Sheets-Sheet l Search R00June 1946- E. w. RIEMENSCHNEIDER EI'AL 2,401,799

RADIO ANTENNA TOWER Filed Aug. 4,- 1941 s SheetS -ShQet 2 i Z! 1 W I 9a,? l 23/ /7 Edi/wad W 171? Wider O and Patented June 11, 1946 RADIOANTENNA TOWER Edmund W. Riemenschneider and Harry Rastetter, Canton,Ohio, assignors to The Union Metal Manufacturing Company, Canton, Ohio,a corporation of Ohio Application August 4, 1941, Serial No. 405,378

6 Claims.

The invention relates generally to antennae or to supports for antennaefor radio transmission, and more particularly to the construction ofhigh towers and masts used in radio broadcasting and transmission.

It is recognized that a single vertical conductor is a very eflicientantenna for radio broadcasting and transmission, but it is difficult tosupport such an antenna particularly as the usual broadcastingfrequencies require an antenna tower several hundred feet in height.Accordingly, many such towers have included a very large number ofstructural members as well as guy wires, and such structural membersabsorb a considerable amount of radio energy and thus reduce theefiiciency of the tower to a substantial extent.

Where the tower itself constitutes the antenna and is of rigidconstruction throughout, the construction and erection of the towerinvolves considerable labor, time and expense. Moreover, such a towermust be very well guyed and structurally very strong to resist windloads, and the nodal vibrations which inherently occur in such astructure.

An object of the present invention is to provide an articulated antennatower made up of novel compression members each having maximumcompressive strength and exceptionally good radio transmittingproperties.

Another object is to provide an articulated antenna tower in which themembers take all of the compression load and the tension forces aretaken by guy wires.

Another object is to provide an articulated antenna tower having selfsupporting tubular members so designed as to give maximum compressiveand wind load strength with minimum weight, and at the same time havinga contour offering a minimum of resistance to wind.

A further object is to provide an articulated tower having flexiblejoints eliminating the occurrence of nodal vibrations and permitting oneor more members to be out of alignment without affecting the alignmentof other members, and without transmitting bending moments to adjacentmembers.

Another object is to provide an articulated tower having flexible jointsbetween tubular compression members each designed to act like a beamagainst wind loads.

And finally, it is an object of the present invention to provide a novelantenna tower which combines maximum radio transmitting efficiency witheconomy of material, which can be erected rapidly and cheaply to anyrequired height, and

which is inexpensive to maintain and has a pleasing appearance.

These and other objects are attained by the parts, elements andstructures comprising the present invention, which are shown by way ofexample in the accompanying drawings and hereinafter described andclaimed.

In general terms the invention may be stated as including an antennatower consisting of a plurality of tubular compression members connectedtogether by means of flexible joints, each compression member being athin elongated tube having its greatest lateral dimension centrally ofits ends, and being gradually tapered from said central portion to theends, and guy wires connected to the upper end of each compressionmember.

Referring to the drawings in which preferred embodiments of theinvention are shown by way of example,

Figure 1 is a fragmentary elevation of one form of improved radio towersupported on an insulator base;

Fig. 2 is an enlarged detached view of one of the novel compressionmembers, with parts broken away;

Fig. 3 is an enlarged fragmentary sectional -view showing the flexiblejoint connecting two of the improved compression members;

Fig. 4 is an enlarged fragmentary view of a suitable insulator basesupporting the tower;

Fig, 5 is a view similar to Fig. 2 of a modified form of the improvedcompression member;

Fig. 6 is a view similar to Fig. 1, showing a. tower comprising thenovel compression members with rigid joints therebetween; and

Fig. 7 is an enlarged fragmentary sectional view of one of the rigidjoints in the tower of Fig. 6.

Similar numerals refer to similar parts throughout the several views ofthe drawings.

As shown in Fig. 1 the improved antenna tower is made up of a pluralityof tubular compression members indicated generally at 6 and connected attheir ends to provide an articulated tower of great height and verynarrow girth. As shown guy wires 1 are connected to the upper end ofeach compression member 6 and suitably anchored in the ground, asindicated at 8.

The ideal shape and design for a compression member is one in which thegreatest strength is at the center, and which tapers gradually from thecenter to the ends. Such a shape or design may be termed an elongatedcigar-1ike shape and gives maximum compressive strength for minimumweight of material, and is particularly desirable in a tower structurebecause it acts like a beam in resisting wind loads. Moreover, the longtapered shape such as shown in Figs. 1 and 2 provides very littleresistance to Winds from any direction, thereby decreasing the effectivewind load on the tower.

As shown in Fig. 2, the novel tubular compression member 6 consists oftwo tapered poles 9 or frusto-conical tubes of substantially equallengths, having their large ends welded or otherwise connected togetherin abutment with each other as indicated at I0, and being in substantialalignment throughout their length to form an elongated tubularcompression member having equal strength in all lateral directions andhaving its greatest strength and lateral dimension intermediate the endsand tapering gradually therefrom to the ends. As shown each compressionmember 6 has ears H secured to and projecting from its upper endportion, and said ears are adapted to be connected to the upper ends ofthe guy wires I.

Preferably, the tapered poles 9 are approximately forty to fifty feetlong, and when welded together make the compression members 6, eighty toone hundred feet long. Thus a radio tower constructed according to thepresent invention may consist of one, two, three or more of the members6 depending upon the tower height necessary for the broadcastingfrequency used.

The outside diameter of the tapered poles 9 preferably varies from aboutfive inches at the small end to eighteen inches at the large end, sothat when two poles 9 are welded together as shown in Fig. 2 to make acompression member 6, the largest lateral dimension of the member is atits central portion and tapers gradually therefrom to the ends, making acompression member approaching the elongated cigar-shape characteristicof an ideal compression member.

The modified form of compression member Ga shown in Fig. is made up oftwo tapered or frusto-conical tubes 9a with a straight tubular section9a welded to their large ends and forming the central portion of thecompression member, the tubular sections being in substantial axialalignment throughout their length, and having equal strength in alllateral directions. The diameter of the straight section 9a is equal tothe diameter of the large ends of tapered tubes 9a, so that member 6aapproaches the alongated cigar-shape which is characteristic of an idealcompression member, and offers little wind resistance. The length ofsaid central section 9a may be about 4; to of the total length of member6a.

The gauge of the tubular members 6 or 5a varies considerably accordingto the height of the tower. Thus the member 6 at the bottom of the towershould be of heavier gauge than the one at the top because of thegreater compression load on the bottom member. For example, where thetower height requires several members, say four members, the bottom onemay be 0 gauge or T e inch in thickness, the next higher one may be 3gauge or /4 inch, the next higher member '7 gauge or r e inch, and thetop member may be 11 gauge or inch. In some cases the bottom one or twomembers may be made of two plies of metal, as for instance two plies of7 gauge or two plies of 11 gauge.

As shown in Figs. 1 and 4 the bottom compression member 6 is supportedon an insulator base l2 which is of well-known construction and forms nopart of the present invention. Such a 4 base is used where the toweritself acts as the antenna, and is not necessary where the tower ismerely a support for the antenna.

As best shown in Fig. 4 the base I2 is anchored by anchor bolts 13imbedded in a concrete foundation l4, and the lower end of the bottomcompression member 6 has welded thereon a base plate l5 braced by gussetplates 15 welded to the pole 9, and the base plate 15 is securely boltedto the top of base H by bolts IS.

The several compression members 6 comprising the articulated tower areconnected together at their ends preferably by means of flexible jointsindicated generally at I! and shown in detail in Fig. 3. The upper endof each member 6 preferably has welded thereon an abutment plate l8 theupper abutment surface is of which is convex or crowned as shown. Thelower end of the member 6 connected thereto and resting thereon has anabutment plate 20 secured to its bottom end and having a flat surfaceabutting the convex surface IS.

A sleeve 2| is preferably welded at its upper end near the bottom end ofthe upper member 6 at the joint and depends downwardly therefrom toencircle the upper end of the lower member 6. The sleeve 2i may bewelded also to the plate 20 by plug welds shown at 22 at intervalsaround the sleeve, and the diameter of plate 20 is somewhat greater thanthe diameter of plate I8 in order to provide a clearance between thesleeve and the plate l8 so that a certain amount of flexibility is hadat the joint. Thus as the tower is erected, if one of the members 8 isslightly out of alignment, the convex surface l9 can rock laterally onthe bottom of plate 20 to take care of the misalignment withoutaffecting the alignment of other compression members in the tower.

As shown an electric jumper cable 23 is provided for electricallyconnecting the two compression members around each joint, and theabutting plates I8 and 20 are provided with registering holes I8 and 20for permitting the passage of service cables up through the tower. Theears H, provided near the top of each compression member for attachingguy wires thereto, are preferably welded to the member 6 so as to belocated just below the sleeve 2| of the flexible joint when the tower iserected, as shown in Fig. 3.

In erecting a radio tower according to the present invention, the bottommember 6 is first raised in position with its bottom end anchored to asuitable base as previously described, the guy wires 1 having beenattached to the ears ll of the member before raising it. The lower endsof the guy wires are then put under considerable tension and anchored tothe anchor blocks 8, and there being a plurality of insulators 24 ofusual construction incorporated in the guy wires.

By means of a gin pole atta bed in usual fashion to the upper end of thebottom compression member 6, the next compressior member 6 is raisedwith its guy wires I attached to its upper end and with the sleeve 2| ofthe flexible joint I! attached to its lower end, and the sleeve ispositioned over the upper end of the bottom compression member. Theupper guys I are then attached to their anchors under a required amountof tension, and then another member 6 may be erected in the same mannerif desired. The amount of tension on the guy wires 1 is calculated totake substantially all of the tension forces to which the tower issubjected, so that the mem- ,bers 8 will take all of the compressionload.

When the improved articulated tower has flexible joints between themembers, the occurrence of nodal vibrations inherent in a rigid tower iseliminated, and said joints permit some misalignment of one or moremembers without affecting the other members.

Under certain conditions it may be desirable to provide an improvedradio antenna tower embodying the novel compression members connectedtogether end to end by means of rigid joints. In Fig. 6, the improvedantenna tower is made up of a plurality of compression members 617 withguy wires 117 connected to the upper end of each compression member 612and suitably anchored in the ground, as indicated at 8b.

Each compression member 6b may include two tapered poles orfrusto-conical tubes 91) having their large ends Welded or otherwiseconnected together in abutment with each other, as shown, or including acentral cylindrical tube as illus trated in Fig. 5; the tubular sectionsbeing in substantial axial alignment throughout their length, and havingequal strength in all lateral directions.

As shown in Fig. 7, the rigid joints between members 61) may include anabutment ring 26b welded on the upper end of the lower member 617, and asimilar abutment ring 211) welded on the lower end of the upper member6b. The rings 26b and 21b are provided with registering bolt holesthrough which bolts 28b are inserted for clamping the rings together inabutment and rigidly joining the members 6b together.

The present antenna tower in its several embodiments consists entirelyof novel compression members having maximum strength with a minimum ofweight, and having a contour which ofiers extremely low wind resistance.It has been determined in actual practice than an antenna made up ofapplicants novel tubular compression members has exceptionally goodradio transmitting and broadcasting properties.

The present improved radio antenna tower is pleasing in appearance, andinexpensive to erect and maintain.

We claim:

1. An articulated radio antenna tower including a plurality of tubularcompression members supported end to end upon one another, meansproviding flexible joints between said members, each of said membersconsisting of tubular sections joined together in end-to-end abutmentand having its greatest lateral dimension at its central portion andtapering gradually therefrom to its ends, and guy wires attached undertension to the upper end of each said member.

2. An articulated radio antenna tower including a pluraliy of tubularcompression members supported end to end upon one another, meansproviding flexible joints between said members, said means including arounded abutment on one adjoining member and a sleeve secured on theother adjoining member and loosely encircling the end portion of saidone adjoining member, each of said members having its greatest lateraldimension at its central portion and tapering gradually therefrom to itsends, and guy wires attached under tension to the upper end of each saidmem her.

3. An articulated radio antenna tower including a plurality of tubularcompression members supported end to end one upon another, meansproviding for limited flexibility of the members relative to each otherat the joints between the members, each of said members consisting oftubular sections joined together in end-to-end abutment and beingtapered convergingly from its central portion to its ends, and guy wiresattached under tension to the upper end of each said member.

4. An articulated radio antenna tower including a plurality of tubularcompression members supported end to end upon one another, meansproviding flexible joints between said members, each of said membersincluding two elongated frustoconical tubes having their large endsjoined in abutment, and guy wires attached under tension to the upperend of each said member.

5. An articulated radio antenna tower including a plurality of tubularcompression members supported end to end upon one another, meansproviding flexible joints between said members, each of said memberscomprising a central cylindrical portion and two elongatedfrusto-conical tubes having their large ends joined in abutment with theends of said cylindrical portion, and guy wires attached under tensionto the upper end of each said member.

6. An upright mast construction comprising a plurality of substantiallyrigid units, each unit having its maximum cross section at the middlepart thereof and being of substantially uniformly reducing tapering formto the two ends thereof, said units being arranged vertically end to endwith their small ends together and in strictly electro-conductiveengagement with each other, means of universally articulated jointconnection between said adjacent ends, and means axially surroundingsaid joint and overlapping said adjacent end portions so as to limit theextent of movement and to center the units at the joint between thesame.

EDMUND W. RIEMENSCHNEIDER. HARRY O. RASTETI'ER.

